130 PRACTICAL ARBORICULTURE 
Frost is not essential for either the ripening of the fruit or for cracking the 
hard shell to release the growing plant, for the walnut often grows in the South 
where severe frosts do not occur, yet they grow as well as those acted upon by 
freezing. 
Neither does the frost injure the seed or trees, both being very hardy. 
The nuts vary in size greatly, and possibly might be improved by selection of 
seed, but the variety of edible nuts of other trees, and especially the European 
thinshelled walnuts which are far better in flavor and are less bulky, would make 
such attempt at improvement unprofitable. 
INSECT PESTS. 
There is a strong odor and a sticky, highly colored sap in the walnut, which 
is obnoxious to most insects. No borers are known to injure the wood, and but 
few attack the foliage, hence its freedom from insect enemies commend it for cul- 
tivation. 
ENGAGE SEED IN ADVANCE, 
Every season inquiries are made for walnuts for seed, but usually it is too 
late to obtain them. They must be engaged in advance. No one can aiford 
to collect them in large quantities and prepare the nuts for planting without 
knowing in advance that they will be wanted. Yet enough nuts could be 
secured to plant thousands of acres if parties desiring them would make their 
wants known before gathering time. 
CULTIVATION. 
It is absolutely a waste of time, money and energy to plant anything and 
then abandon it to nature. 
\Walnut trees must be cultivated the same as corn or other crops if the 
best success is expected. This must continue for four or five years, or unul 
the ground is so shaded as to keep down grass. 
Of course this pertains to land not in forest, for there cultivation has a 
better substitute, a loose mould and mulching of leaves. 
The man who plants a forest of any kind, and relies upon nature to do his 
pruning, must plant very thickly and will leave the farm, entailed, to his 
great-grandchildren, who may receive some benefit. 
Pruning is not expensive—it is much cheaper than paying interest on a 
long-time investment while waiting for nature to do the work. 
Cut off a side branch when less than an inch in thickness and the saw 
will not be required to remove it when a foot through. 
Rapidity of growth will depend upon treatment rather than other causes. 
From several hundred measurements I have found that with room to 
secure nourishment, and not in a hard sod, the average growth up to thirty 
years is two inches girth increase per annum. A tree twenty vears old should 
be in girth 4o inches or have a thickness of 1314 inches. 
As the walnut became more scarce from the excessive demand its value 
arose to a fabulous price. .\gents scoured the country paying enormous sums 
